Portable computers of the type commonly referred to as laptop computers or notebook computers are becoming increasingly popular. An existing notebook computer has a standby mode in which certain peripherals are placed in a reduced power mode, including deactuation of the display, and in which the processor is halted in order to conserve power. While the standby capability has been entirely appropriate for its intended purposes, it has not been satisfactory in all respects.
In particular, when the system enters the standby mode, it is very visible to the user that the standby mode has been entered, because the computer turns the display off and halts program execution. Further, if the user presses a key or a push-button switch in order to exit standby mode and return to normal operation, a noticeable time interval usually elapses before the system is again running normally, which can be very annoying to a user.
It is therefore an object of the present invention to provide a computer system having a further mode which provides a level of power reduction over a normal operational mode but which is effectively imperceptible to the user.